A couple of comments about what the factors are to your question. Short answer a 25hp and at least a 12' dinghy.
- rider weight
The larger a rider the more power needed. My 8 yr old can WB behind an 8' with a 9.9 no problem, he weighs 55lbs. I am 205lbs and the smallest I have attempted and was able to ride behind is a 15hp and it requires unique dinghy/wakeboard skill which is the second point
- rider skill
An experienced rider understands the dynamics of both the board and the dinghy getting onto plane. You can 'time' the launch of the dinghy and pop up quickly with an underpowered outboard
. It takes skill and understanding of thrust sharing between the two hulls your trying to plane simultaneously but can happen.
- optimize the dinghy
The little mini tower on the back helps. It changes the angle of the pull which lifts the rider slightly rather than dragging the rider during launch which promotes quicker time for the board to plane. Second, put a long fuel
supply line on a larger tank and secure to the nose. This gets the dinghy on plane quicker which is allows for more thrust for the rider to get onto plane. In all scenarios the driver should sit as far forward as possible to promote the dinghy on plane quickly.
short of it is: Less experienced, larger riders = much bigger tow boat. Smaller, experienced riders who are willing to learn the dinghy nuances no problem. Check out Sailing Delos on youtube they wakeboard a lot behind their 25hp. I have met them in person, not small guys so again you can learn your dinghy but don't expect guests on the boat for the weekend to figure it out. I would learn to Kiteboard if I were you, same fun, always wind
in the trades and an optimal experience instead of a limited one and doesn't kill gas.